MGL Avionics User Forum

Rainer, if it is ignition interference, would moving the antenna to the rear of the aircraft help?

Will an antenna with a higher dB rating help overcome ignition noise? Most active gps antenna claim 28 dB, but I found one that claims 40 dB.

No that will not make a difference.
If you have something that creates a signal at 1.5Ghz where the GPS operates using an antenna with a higher gain will simply amplify the interfering signal by the same amount.

If it's your ignition leads that are radiating install a ferrite over each (close to the plugs). Use a small ring ferrite and secure with a cable tie. They should be very effective at that high frequency.

Hi All,

Here is something of interest, as I was going through the menu settings for my Voyager EFIS on the sim program when I came across the "GPS Sensitivity Setting" its setting options are, High/Automatic/Normal/Low.

I then went searching for written details through many MGL Documents about these setting, sadly as DutchRoll said some time back, these MGL documents really do need to be collated into some index with all information for particular items into the one document.

Anyway moving on, I did find a paragraph about this "GPS Sensitivity Setting" and the way I took it, if you select the high setting, this could cause GPS instability if you have EMI/RF noise in your electrical system. So after reading this about the "GPS Sensitivity Setting" I checked my two EFIS setting and found both set to high.

Before finding this, I had tried a few thing to track down my GPS dropouts, like changing the order of my negative bus connections (this helped a lot) replaced my GPS antennas, re-positioned the antennas (this helped I believe). For anything else, I would have to go back through this post to see what else I did.

But over my last 15 hours of flying, I have only had couple of GPS dropout for a second, compared to the 30 min flight where one of my EFIS's GPS was dropping out every few minutes, then every 20 seconds until the GPS crashed and I had to reboot the EFIS.

So after finding this little bit of information about the "GPS Sensitivity Setting", I am wondering, if I had changed the "GPS Sensitivity Setting" would this helped to resolve my GPS drop outs.

I hope this might help someone else to quickly solve or reduce any GPS dropouts if their GPS issue starts whilst they are on a cross country nav. and this could be something to check and change in flight.


Cheers
JimJab

Hi All,

Well it's been a while since my post where I thought I had solved my pilot side EFIS's GPS from dropping Sat signals from EMI.

Its been 12 months and enough flight hours without any further GPS drop outs. So I am quietly confident I have solve my GPS dropouts and hopefully it's a thing of the past for now.

I did take the advice from a fellow MGL'er on the forum and purchased two of the newer MGL GPS Boards just in case I needed to have the more recent GPS chips for my Voyagers so it can handle more EMI interference.

But when I received these newer GPS Boards, my GPS's was no longer dropping out or having EMI issues, so I have not installed these newer GPS Boards yet and for the moment, I don't see the need to.

For those people who have been reading my many posts on this forum, know I have been fixing an array of different EFIS issues, which strangely have all been with my pilot EFIS's and my co-pilot EFIS has had little issues.

Anyway, I can say over the last 12 months both my MGL EFIS are now running sweet as. Still have my fuel flow system and calibrations to get up to speed, but after the other day in what I found, I think this may be much closer now.

So, I am now very confident and pleased with how my Pilot/EFIS GPS is operating over the last 12 months, I would be happy to fly Australia with both my 13 year old Voyagers. They are really a sweet bit of gear for the amount of situational awareness as a pilot and with the graphic flexibility the MGL page designer give me.

Hats off to MGL and Rainer for this product.

Cheers
JimJab